/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package org.apache.iotdb.db.protocol.influxdb.function.aggregator;

import org.apache.iotdb.db.mpp.plan.expression.Expression;
import org.apache.iotdb.db.protocol.influxdb.constant.InfluxSqlConstant;
import org.apache.iotdb.db.protocol.influxdb.function.InfluxFunctionValue;

import java.util.List;

public class InfluxSpreadFunction extends InfluxAggregator {
    private Double maxNum = null;
    private Double minNum = null;

    public InfluxSpreadFunction(List<Expression> expressionList) {
        super(expressionList);
    }

    @Override
    public InfluxFunctionValue calculateBruteForce() {
        if (maxNum == null || minNum == null) {
            return new InfluxFunctionValue(null, 0L);
        } else {
            return new InfluxFunctionValue(maxNum - minNum, 0L);
        }
    }

    @Override
    public InfluxFunctionValue calculateByIoTDBFunc() {
        if (maxNum == null || minNum == null) {
            return new InfluxFunctionValue(null, null);
        }
        return new InfluxFunctionValue(maxNum - minNum, 0L);
    }

    @Override
    public String getFunctionName() {
        return InfluxSqlConstant.SPREAD;
    }

    @Override
    public void updateValueBruteForce(InfluxFunctionValue functionValue) {
        Object value = functionValue.getValue();
        if (!(value instanceof Number)) {
            throw new IllegalArgumentException("not support this type");
        }

        double tmpValue = ((Number) value).doubleValue();
        if (maxNum == null || tmpValue > maxNum) {
            maxNum = tmpValue;
        }
        if (minNum == null || tmpValue < minNum) {
            minNum = tmpValue;
        }
    }

    @Override
    public void updateValueIoTDBFunc(InfluxFunctionValue... functionValues) {
        if (functionValues.length == 1) {
            double tmpValue = ((Number) functionValues[0].getValue()).doubleValue();
            if (maxNum == null) {
                maxNum = tmpValue;
            } else if (tmpValue > maxNum) {
                maxNum = tmpValue;
            }
        } else if (functionValues.length == 2) {
            double tmpValue = ((Number) functionValues[1].getValue()).doubleValue();
            if (minNum == null) {
                minNum = tmpValue;
            } else if (tmpValue < minNum) {
                minNum = tmpValue;
            }
        }
    }
}
